Headlight for vehicles



Oct. 23, 1923. 1,471,767

w. H. WOOD HEADLIGHT FOR VEHICLES Filed Oct. 6, 1920 2 Sheets-Sheet 1Oct. 23, 1923. 1,471,767

w. H. WOOD HEADLIGHT FOR VEHICLES Fil l gct. e, 1920 2 Sheets-Sheet 2Patented Oct. 23, 1923.

WILLIAM H. WOOD, OF CLEVELAND, OHIO.

HEADLIGHT FOR VEHICLES.

Application filed October 6, 1920. Serial No. 415,021

To alt whom it may concern:

Be it known that I, VILLIAM H. VOOD, a citizen of the United States,residing at Cleveland, in the county of Cuyahoga and State of Ohio, haveinvented a certain new and useful Improvement in Headlights forVehicles, of which the following is a full, clear, and exactdescription, reference being had. to the accompanying drawings.

This invention relates to headlights, especially those employed on motorvehicles. Safety and convenience of vehicle operation in the darkrequires the illumination of the ground for a considerable distance infront of the machine and to some extent at either side thereof, yet alsorequires keeping the rays of light sufficiently low towards the sideexposed to oppositely moving vehicles to avoid blinding the eyes of thedrivers thereof. Furthermore the intensity of the illuminationthroughout the illuminated area should vary from point to pointaccording to the obvious requirements of operation, this comprising apowerful distance beam for fast driving in a straight path combined witha softer light closer to the wheels and a laterally directed curb lightsufficient to enable the avoidance of obstructions and the recognitionof persons at the curb-side of the vehicle. Not only are theseconditions desirable to the driver but many of them are required by lawin the different States, which laws prescribe the intensity limits in.different parts of the field. While these laws vary greatly their commonpurport is that above indicated and all can be complied with by a devicehaving the above characteristics.

Lenses have heretofore been developed possessing most of the foregoingrequirements but these are necessarily expensive to make and of afragile nature, while their employment does not dispense with thenecessity of using a reflector nor of focusing the light sourcecarefully with reference thereto. The objects of my invention are theprovision of a. simple, one-piece, reflector which shall satisfy all theforegoing needs and at the same time dispense with the necessity of aspecial lens; the provision of a reflector of the desiredlight-distributive character which shall be no more expensive tomanufacture than the plain parabolic reflector, which shall possess thequalities mentioned without serious irregularities of shape or markeddivergencies in surface,

which can be easily manufactured from sheet metal by commercialprocesses and conveniently polished and finished, which can be focusedwith ease and within a comparatively wide permissive range; and whichcan be employed in present headlights without any other changewhatsoever; while further objects and advantages of my invention willbecome apparent as the description proceeds. The present inventionconstitutes an improvement upon the device disclosed and claimed in myformer patent granted July 31, 1917, No. 1,235,275 and it isdistinguished therefrom chiefly in the definition, location and relationof the various reflector segments and the relations of the light sourcethereto, being a continuation in part of my application No. 324,338,filed September 18, 1919. The objects of the present inventiona-retherefore identical with the general objects defined in said patent, thesame being secured in a larger measure and to a more accurate degreethan heretofore.

In the drawings accompanying and forming a part of this application Ihave shown certain illustrative embodiments of my invention togetherwith certain diagrammatic views illustrating the scientific theory ofthe same and setting forth graphically the purposes of. the differentparts of my improved reflector. In these drawings Fig. 1 is a verticalsection through a preferred form of reflector embodying my improvements;Fig. 2 is a. front view of the same; Figs. 3 and 4; are diagrammaticviews illustrating the shape, position and function of one element ofsaid reflector; Figs. 5, 6 and 7, S are similar views illustrating. butin exaggerated degree, the shape, position and function of otherelements of said re flector; Fig. 9 is a side elevation of an automobileheadlight provided with my improved reflector and illustrating thedistribution of the rays; Fig. 10 is a top plan view of the same showingthe general outline of the light pattern; Fig. 11 is a graphiclight-chart; Fig. 12 is a horizontal sectional view of my improvedreflector illustrating the result of displacing the light sourcelaterally; and Figs. 13 and 14: are face views of modified reflectors embodving my improvements.

My improved reflector comprises portions of a plurality of paraboloidsurfaces arranged in definite relations towards each other and towardthe light 2 portions are represented at 11, B and L1, their axes at a a,12-4) and o-c, respective ly, their focal points being indicated at a,Z) and 0, respectively. The lamp axis coincides with the axis a-a andrepresented by L-L, in views where a-a does not occur, and S representesthe lightsource which is located upon the horizontal plane containingthis axis, but preferably slightly to one side thereoi tor a reasonwhich will later appear.

The section A subtends less than 180 of are as illustrated in Figs. 2and i terminates at a point short of its vertex as shown in Figs. 3 andl, its axis aa sul stantially coinciding with the lamp axis as snown inFig. 1. The light source, which is ordinarily an electric lamp filamentof the type concentrated into a small space, is located in the plane ofthis axis close to,

but in front of the focal point a. as a consourc sequence, of this, allrays of light originating I at that point of the source nearest thefocal point will be thrown "forwardly in a direction substantiallyparallel to the plane of the lamp axis indicated at e-e in 3, whilethose ori 'inating at the extreme top and extreme rorwarc parts of saidsource will be thrown downwardly across the axis as shown at f.

with such a slant as to cast a glare into the eyes of drivers and drattanimals moving in the opposite direction, the margin of the portion A atthe side nearest the curb is terminated at a sufticient height above theplane of the lamp axis to pre vent any rays, even from the most extremeportions of the source, from being thrown across the road; but inasmuchas the existence of a certain amount of illumination on the curb side isnot only conducive to driving-comfort but is required b T the laws insome localities, the opposite margin of the portion A isconvenientlycontinued to a sufiiciently low point to yield the amount ofillumination desired. This point may even be as low as the plane or thelamp axis, thus affording an asymmet ical arrangement as indicated at aand a. in Fig. i, the wider gap being on the curb side.

Thesection B is a comparatively narrow zone taken from a portion lyingnear the vertex of a larger paraboloid surface and constitutes the sideWing's described and claimed in my Patent No. 1,325,275. Its axis 6 isinclined downwardly at a con- "Lone argin of the section A, the focalpoint 1 also falls ahead of the light source; all of these conditions(namely, the inclination of the axis, the vertical displacement of thesource. and the location of the source be hind the focal point) combineto produce a downward divergence of all light rays which fall thereon asshown at K anc L in Fig. 5, thus gi'vingr rise to the beams indicated inbroken lines at Q, in Figs. 9 and 10. This zone is not made of equalwidths upon its two sides, but the side nearest to the curb is madewider as indicated at B and the opposite side narrower as shown at Bthus coi'i'ipensating :tor the inquality oil the section A. In fact,within the practical and legal requirements of illumination the narrowside of this zone can be omitted entirely as shown in Fig. 14-, but thisentails practical dilliculties in construction which will e referred tolater.

'i no section C is here shown as subtending approximately 180 of arc andas terininat ing substan ia-lly at its vertex as shown in i igs. T and8, its axis oc being inclined downwardly relatively to the lamp axis butby an angle less than that of the axis 7)-7). Its size is such that itsfocal point (2 lies in. front of (or at least not behind) the mostadvanced portion oi the light source,

the latter, owing; to the inclination of the axis c-c, also lying abovesuch focal point.

suit ot this relation of lie. 1 source and focal point, all the raystelling; upon this portion oi the suritace C are divers ail. as shown bythe lines m, a and 0 of Fig. 7, and hence give rise to the beamsindicated at 3- in Figs. 9 and it). The inclination ot the portion Cprevents any of the rays theretrom being thrown sufficiently high todazzle the eyes of man or draft animals moving in the oppositedirection. It is generally n'iade of a larger iaraboloid than thesect-ion A and its shape the front, owing to its inclination, issomewhat. elliptical.

The point of intersect-ion of the various is unimportant. They mayinterstfi the same point or at diiterent points. Likewise it isrenerally unimportant as regards my invention exactly how near to thevertex of the different pa-raboloids any of thesesections extend,provided only that the herein-described relations between axes and focalpoints are preserved. This rane of choice enables a choice of sectionswhose margins shall coincide at every point without the formation ofhollows or ridges which would weaken the device, cause shearing in thedies, or impede the polishing operation. lVithin the same limits thesizes 'of the paraboloids are unimportant, al-

though it is this variation in sizes which largely produces the desiredrelation of focal points while maintaining the vertices approximatelycoincident. Within these limits a slight variation in relative sizesassists materially in matching the margins of adjacent portions. \Vithinthe same limits the width of the portion B is susceptible of widevariations; the top line of the part B is fixed by the illuminatingconditions heretofore described, but the bottom line thereof isdetermined only by the requirements of meeting smoothly the margin ofthe lower section. Likewise the top line of the part B is fixed by therequirements of lateral illumination on the curb Side of the machinewhile the bottom edge is variable to enable a smooth joint with. thelower section. Excepting for this last consideration it would bepossible to omit the wing B entirely as heretofore suggested; butpractically the only way of matching two unequal paraboloid sectionstogether is by the interposition of a third paraboloid section,wherefore I prefer to retain some ves tige of this wing. It will beunderstood that the wings B and B need not be segments of the sameparaboloid surface but may be of different sizes or taken at differentangles.

As an example of a successful reflector embodying my improven'ients Iwill instance the following. Upper section 7-1; in. diameter, 3 in.deep, 1 in. focal distance, margin at heel 1;} in. from axial plane andat each side in front 5} in. from axial plane; lower section 8 in.diameter, 3- in. deep, depressed i; in. at mouth focal distance 1 inch;intermediate section has a focal dis tance of 1 inches and is leaneddownwardly inch at the face, thus producing two wings each 1 in. wide atthe mouth and inch wide at the heel. To render the wings unequal the topsection is shortened inch at the curb side and the zone sect-ion rotatedcorrespondingly so as to justify the line. The lain ii axis lies within.the limits of this zone.

Further to control the rays of light and to produce the asymmetricalfield of illumination hereinbefore mentioned with the maximum at thecurb side, I preferably displace the light source slightly to one sideof the vertical plane. The result of such displacement is to move thelight beam transversely of the lamp axis by an amount varying with thedistance. of the source from the transverse plane which includes. thefocal point. The greater the initial deviation of the beam, the greaterwill be the effect of such lateral displacement; hence the effect on therays thrown from the section A is comparatively small, since the lightsource lies especially close to the focal point of this section; in.other words the distance beam is not much affected, while the effectupon the light reflected by the side wings is particularly great.Therefore by shifting this light source slightly towards the left thedirection of the main beam P is very slight- 1y changed, the directionof the secondary beam R is somewhat more changed, while the direction ofthe portions Q,Q are so deflected as will the entire light field towardsthe curb and away from the center of the road as shown in Fig. 10. Itwill be understood that both headlights are preferably made in the samemanner and asymmetric in the same direction, their effect being additiveso far as they overlap each other, and the illumination of the left handlight extending not beyond the center of the road. However thisdisplacement of the field by displacement of the source laterally is notconfined to a reflector having such unequal side wings but is equallyimpoi-ta nt with one having equal side wings as shown in Fig. 13 andused in connection with a plain paraboloid reflector will great- 1yreduce its objectionable qualities.

The result of such lateral displacement of the light source is shown inF 12, where in V represents a horizontal section of a paraboloidreflector, V-V represents its axis, and V its focal point. Light raysoriginating at V are always reflected parallel to the axis as shown at Vand a lateral shift to the point V only moves the reflected beam asshown in the dotted line V. Light rays originating at W, on the axisforward of the focal point are converged across the axis as shown at Vand a lateral shift to the point V moves the reflected beam in theopposite direction and through a much greater angle as shown by thedotted line WV. Light rays originated at X, on the axis behind the focalpoint are diverged as shown at X and a lateral shift to the point Xmoves the reflected beam through a similarly great angle in the oppositedi rection as shown by the line X It will be understood that operativeheadlights always generate both concentrated and diffused. beams, theformer arising from those re" gions of the source which lie nearest thefocal point and the rest arising from those regions of the source whichare further away therefrom.

By reason of the laterally inclined or axially rotated position of thesegment A, and of the difierent heights of the intermediate segment orsegments upon the two sides of the reflector, and the lateraldisplacement of the light source S, the light attern becomes asymmetricindicated oproximately by the line a. in Fig. 11, all aring rays beingremoved from th road e of the vehicle, and with the deflection t sul'licient light towards the curb to avoid anger of striking obstacles orpedestrians on that side of the street. I have refrained from describingthis as the right hand side ot he vchic of the well known fact iebecause that in some countries the vehicles pass to the left of each.other, and the left hand sine becomes the curb side. Likewise I donotconline myself to a construction wherein all three of thesedeflectingfeatures are used except as I have specifically claimed thesame as coexisting in single structure, since any one of these featureswill some times be found sutiicicnt for some purposes. il hile it willbe understood that it is entirely possible to construct such a reilectoras herein described by actua ly cutting out sections or slices of thr 3separate paraboloids and physically uniting them at their edges, myimproved reflector is prettcrably made from a single sheet of metal. bydrawing it in dies of the requisite form to afford the necessary shapesto the dine ent portions; and in that event a portion oi? the originalplate is left as shown at T to constit ie a stihening ingeand attachingrim .vhich can be provided. with bol receiving slots ll or othersecuring devices if desired. The exterior of this rim is pretcrably madecircular, its width being sutficiently great to compensate for thenoncircula character of the concave portions ot the reflector as shownin Fig. 2. Experience shows that a reflector ot this nature can be drawnby a single operation. and pol.- i'shed with the same speed and by thesame apparatus as is used in connection with the plain paraboloidreflectors.

J: advantages of this reflector T he chieiv are that it dispenses withthe necessity for any s1 ecial type of lens and enables a mere pane ofglass to be employed; owing to its peculiar vterm, the limit oftolerance as regards the adjustment of the light source are very wide,thus enabling adjustment to be made by unskil ed persons and stillsecuring a character and distribution of light which will enablecomfortable driving and comply with legal requirements. The chietadvantages of this reflector over that shown in my former patent arethat the side wings possess a definite shape which can. be made about anaxis of revolution and that the light field possesses the asymmetricalshape described.

It will be understood that I do not re strict myself to the exactdetails herein described except as recited in my claims.

Having thus described my invention, what I claim is:

'1. A reflector body having a pair of upper and lower surfaces ofrevolution "facing each other on opoosite sides the lamp axis, thelateral margins of said surfaces being spaced apart by unequal distancesand con nected by interposed surfaces of revolution of smallercurvature.

A reflector body having a concave portion substantially located upon oneside of a longitudinal axis and also having at each side of said axis awing portion subtending the axial region, the upper parts of said wingportions being inclined inwardly toward each other and one of said wingportions being wider than the other.

3. A one piece metal reflector for automobile headlights comprising apair of oposed se mcnts o't unccual sized naraboa l l loids located uponopposite sides of the r Hector axi and having at their open ends anintegral circular flange which is perpendicular to said axis, the axisof the smaller paraboloid segment coinciding with said reflector axisand that the larger paraboloid diverging from said axis, the smallerparaboloid segment subtending less than 180 and having its vertexlocated ahead 03": toe vertex of the larger paraboloid so as to bringthe focal points ot the two segments more closely together, and anintermediate inwardly leaning section connecting the margins ot saidsegments.

i. A lamp reflector made of a single piece of sheet metal having itsupper and lower portions formed as separate surfaces of revolutionarranged substantially about a common horizontal axis, and having itsintermediate portions formed separately from both surfaces and inclinedtoward each other, such intermediate portions being of unequal. angularextent upon the opposite sides of the reflector.

5. A reflector having a pair of opposed semi-parabolic surfaces, onebeing of larger diameter than the other and the two surfaces beingslightly offset at their verticcs, the adjacent marginal edges ot. suchparabolic sections being joined by a reflecting surface which isseparate from earn of them and is inclined at every point toward. thesmaller parabolic surface and narrower on one side of the reflector thanupon the other.

6. in a headlight 7 the combination with a. light source ot a one piece,sheet metal, re hector having upper and lower opposed paraboloid so-rents and interposed lateral segments merging with the accnt marginsthereof, the upper segment converges the light falling thereon, thelower segment diverges the rays falling thereon, and the lateralsegments are wider at the mouth of the reflector than at the apex ant.are of uir equal angular extent.

7. A headlight for vehicles comprising a reflector made in one piecehaving upper and lower opposed paraboloid surfaces whose margins arespaced apart, such upper surface subtending less than 180 and thelateral margin of said upper surface which is upon the curb side of thevehicle being located. at a higher level than the other margin thereof,and a paraboloid surface of smaller curvature connecting the adjacentmargins of said upper and lower segments, and having its axis locatedher ath the lamp axis.

S. A headlight for vehicles comprising in combination. a reflectorhaving its upper and lower sides conforming to segments of differentparaboloids facing each other upon opposite sides'of a common axis, anda seg ment of a third paraboloid interposed between and connecting thefirst two segments, at one side of said re rector, said last paraboloidhaving its axis located below said common axis. and a light sourcelocated on substantially the same plane with said common axis but uponthe side thereof which is opposite to the curb side of the automobile.

9. A headlight for vehicles comprising a reflector having a pair ofopposed semiparabolic reflecting surfaces arranged. in flaring relationto each other, the axis of the upper surface coinciding substantiallywith the lamp axis and the adjacent marginal portionsvof said parabolicsurfaces being spaced apart unequal distances, said first surfaces beingconnected upon that side which shows the widest separation by a thirdparaboloid segment whose axis is disposed below the lamp axis, incombination with a light source located substantially upon thehorizontal plane of the lamp axis and at the side of that axis uponwhich the first mentioned parabolic surfaces approach most closelytogether.

10. In an automobile headlight. a one piece sheet metal reflectorcomprising seg ments of three paraboloid surfaces, one of said segmentssubtending less than 180 and having its axis substantially horizontal,another located opposite thereto and having its axis inclined toward theroadway, and the third located intermediate the first two and consistingof an eccentric paraboloid zone whose axis is inclined toward theroadway.

11. In an automobile headlight, a one piece, sheet metal reflectorcomprising two semi-paraboloid portions located opposite each other, theaxis of one of said portions substantially coinciding with the lampaxis,

and a, paraboloid zone interposed between said first two portions andhaving its axis oblique to the lamp axis, said lamp axis fallingwithinthe region defined by said zone, and the margins of said third zoneterminating at unequal distances above the horizontal.

12. In an automobile headlight, a one piece, sheet metal reflectorcomprising segments of three paraboloid surfaces, one of which subtendsless than 180 and has its axis substantially coincident. with the lampaxis, another of which consists of a paraboloid zone whose axis liesbelow the lamp axis, the third being substantially a semiparaboloidwhose focal point lies below and outside that-of the first namedportion, in combination with a light source located between said focalpoints and to one side of the lamp axis.

13. In an automobile headlight, a one piece, sheet metal reflectorcomprising segments of three paraboloid surfaces, the uppermost beingsubstantially a sen'1iparaboloid which subtends less than 180, thelowermost being a semi-paraboloid of larger size with its axis inclineddownwardly and forwardly, and the intermediate segment being a zone of aparaboloid of still larger size, having its axis below the axes of thefirst two segments and having the height of its upper margins unequal atthe two sides of the reflector.

14. In an automobile headlight, a reflector comprising three paraboloidsegments, the uppermost being substantially a semi-parab oloid whichsubtends less than 180, the lowermost being a scmi-paraboloid of largersize with its axis inclined downwardly and forwardly, and theintermediate segment being the eccentric zone of a paraboloid whose axisis still further inclined downwardly and forwardly, the margins of theadjacent segments merging smoothly together and forming a continuousreflector free from abrupt corners.

15. A reflector comprising two opposed semi-paraboloid portions arrangedwith their axes at an oblique angle, and an intermediate paraboloidportion whose edges meet the edges of the first portions at all points,and whose upper margins lie at diiferent heights upon opposite sides ofthe reflector.

16. A reflector comprising two opposed semi-paraboloid segments arrangedwith their axes at an obhque angle and an intermediate paraboloid zone,such zone lying entirely to one side of the vertex of the pa-raboloidfrom which it is taken and the margins of said zone making a flush jointwith the margins of the adjacent paraboloid segments.

17. A one piece sheet metal reflector comprising segments of two opposedsemiparaboloid surfaces arranged opposite each other with their axesdiverging, and an intermediate paraboloid zone whose margins coincidewith the margins of both of the first segments and whose axis crossesthe axis of one of the first segments.

18. A reflector comprising two opposed semi-paraboloid segments ofunequal size arranged with their axes at an oblique angle and anintermediate segment consisting of a paraboloid zone, such zone beingtaken entirely to one side of the vertex of its generating paraboloidand said last named axis being oblique to the axes of both toe firstnamed segments.

19. In a lamp a one piece, sheet metal reflector comprising segments oftwo opposed semi-paraholoid surfaces of unequal size arranged onopposite sides of the lamp axis with their axes at an oblique angle toeach other, one of said segments subtending less than. 180 and havingits mar-g ins spaced at unequal distances from the horizontal plane, anda pair of intermediate paraboloid segments Whose margins coincide withthe adjacent margins of said first segments and Whose normals everywherelie beneath said lamp axis, the lamp axis lying Within the limits of theZone defined by said last named segment.

In testimony whereof, I hereunto aiiix my signature.

WILLIAM H. VJOOD.

